FIG. 1 is a diagram showing a related art configuration.
As shown in FIG. 1, conventionally, electricity generated from fossil fuel and renewable energy sources of a system is provided to a load and a battery exchange station. The electricity is unidirectionally transmitted from the system to customers.
The battery exchange station is a place where the battery of an electric car can be swapped. The battery exchange station is equipped with multiple batteries that can replace the batteries of electric cars, and the batteries are charged with electricity coming from the system. The batteries equipped in the exchange station are batteries for electric cars, and cannot therefore store large amounts of electricity.
Renewable energy generation such as fuel cell power generation, wind power generation, and solar power generation has been deployed in the system to provide generated electricity to the system. However, renewable energy generation such as wind and solar power generation is highly affected by the weather, which makes it difficult to secure a steady and continued supply of electricity to a load, resulting in low utilization. Especially, fuel cell power generation, for example, is rendered unavailable if the battery exchange station is disconnected from the system or load due to an abnormality in the system or load, because fuel cell generation is available when the battery exchange station is connected to the load.
These limitations lead to limitations in the operations of the system and battery exchange station. Since the system and the battery exchange station are configured to provide electricity unidirectionally, excess electricity, if any, in the batteries equipped in the battery exchange station cannot be transmitted to the system, thus making the excess electricity unavailable. In particular, even in case of emergency such as peak time, blackout, etc which require power supply to the system, any excess electricity in the batteries cannot be provided to the system because electricity is transmitted unidirectionally.
Moreover, the batteries equipped in the battery exchange station cannot store a large amount of electricity, and therefore excess electricity in the batteries alone does not ensure the proper supply of electricity in case the power supply to the system is needed.
As a smart grid replaces the existing electric power networks, known as uninterruptible power supply (UPS) to a load, charging of electric cars and electric car batteries, bidirectional transactions of excess electricity or surplus electricity between suppliers and consumers, and renewable energy generation are in the spotlight. In line with this, there is a need to overcome the above-mentioned problems in order to improve operations between a system and a battery exchange station and achieve a variety of functions and benefits of the smart grid.